Electric precipitator



.im 3o, 1940.

H. A. WINTERMUTE ELECTRIC PRECIPITATOR Filed Dec. 22, 1937 5Sheets-Sheet 2 jm 30 1940 H. A. WINTERMUTE 2,188,695

ELECTRI C PRECIPITATOR Filed Deo. 22, 1937 5 Sheets-Sheet 5 Jan, 30,l1940.

H. A. WINTERMUTE ELECTRIC PRECIPITATOR 5 Sheets-Sheet 4 'Filed Deo. 22,1937 Jam 3G i94a H. A. WINTERMUTE 2,188,695

` ELECTRIC PRECIPITATOR Filed Deo.12l2, 1957 5 Sheets-Sheet 5 @WWA/136.

Dit

Patented Jan. 30, 1940 PATENT OFFICE ELECTRIC PRECIPITATOR Harry A.Wintermute, Plainfield, N. J., assigner to Research Corporation, NewYork, N. Y., a corporation oi New York Application December 22, 1937,Serial No. 181,239

24 Claims.

l The invention relatesto a method and apparatus for electricallytreating iluilds and particularly to the removalof suspended particlesfrom iluids comprising the use of apparatus including a. dischargeelectrode system and a plurality of nondischarge electrode systems whichare separately or differently connected to or influenced by meansproviding electrical energization..

Typically the apparatus of the invention comprises essentially adischarge electrode system and two non-discharge electrode systems. Oneoi the non-discharge electrode systems is positioned andenergized toactas a collecting electrode and the other non-discharge electrode systernacts as an auxiliary or intermediate electrode, or the two non-dischargeelectrode systems alternately function as collecting and auxiliaryelectrodes. The two non-discharge electrode systems are so mounted andconnected electrically that the electric fields between each of thesesystems and the discharge electrode system are different at any giveninstant. They may be so connected to a source oi current throughsuitable energy-directing devices that an electric potentialisconnectedv between the discharge electrode system and each of thenondischarge electrode systems alternately. In the intervals betweenpositive energization the nondischarge electrodes may be (ie-energizedby proper connections, or they may be allowed to oat in the eldterminating on the other electrode, by so arranging the connections inthese intervals that the electrode system which is to iioat issubstantially insulated from the other electrode systems. If one of thenon-discharge electrode systems always functions as the principalcollecting electrode, it may be arranged continuously to float in theelci terminating in the auxiliary electrode system by substantiallyinsulating it from the discharge and the auxiliary electrode system sothat the field to the collecting electrode system is at all times aninduced" field.

A principal object of the invention is to provide improved means forelectrically removing suspended particles from uids vcomprisingdischarge electrodes and a novel arrangement of non-dischargingelectrodes with energizing means therefor whereby an efficient removalof the particles withapparatus of small size is ob- (Cl. IBB- 7)velocity exists adjacent said electrodes which provides conditionsfavorable for precipitation of the suspended particles.

An object of the invention is to use a plurality of electric fields tocharge suspended particles 5f' in a fluid stream. and cause theparticles to migrate into a zone where the uid is moving at low velocityand across which an electric field is maintained a sufficient proportionof the time to insure eiiicient precipitation of the particles. 1"

Another object of the invention is to electrically remove suspendedparticles from a fluid stream and collect them adjacent electrodesurfaces where they are agglomerated and precipitated by novel andefilcient means comprising ufboth electrical and mechanical forces.

The means by which the above-mentioned and other objects of theinvention are realized will now be described with the aid of thedrawings in which:

Fig. l is a plan View of a section, taken at I-I of Fig. 2, showing apreferred embodiment of apparatus constructed in accordance with theinvention; l

Fig. 2 is a side elevational view, in section; 25 taken at 2--2 in`ilig. 1, of the preferred apparatus;

Fig. 3 is a cross-sectional view of the preferred apparatus taken at -Sin Fig., i;

Fig. iis a diagrammatic representation of an 30 arrangement of switchingand rectii'ying apparatus suitable for the energization oi the apparatusshown in Figs. 1 to 3;.

Fig. 5 is a diagrammatic representation in partial sectional elevationci another embodiment of 3f the invention;

Fig. 6 is a fragmentary section on line -l-S of Fig. 5;

Figs. '7, 8 and 9 illustrate alternative schemes, within the scope ofinvention for arranging the 40 electrical connections between theelectrode and iii the current source, and

Fig. l@ is a sectional elevation of an embodiment of the inventionparticularly adapted for the electrical treatment oi' liquids.

Apparatus comprising a preferred embodiment of the invention will bedescribed as applied to the removal of suspended solid particles fromgases. Many of the forces acting, conditions set up, and resultsobtained will be realized when 59 apparatus constructed in generalaccordance with the following description is applied to the treatment ofliquids.

Referring to Figs. l, 2 and 3, numeral l identifles a casing or chamberin which the electrodes 55 members d which are in-turn dependent fromcasing I and to which they are electrically connected, comprise what arecommonly knownas collecting electrodes and provide the surfaces uponwhich much of the suspended matter is electrically precipitated. Theinside lateral surfaces of casing i also serve as collecting surfaces.Spaced from plates 5 are auxiliary electrodes 6. These electrodescommonly, as here shown, com prise vertically extending rods E', spacedhorizontally from one another and from plates 5 and are supported byhorizontally extending members 1 which are in turn supported by members8 resting on insulating means 9 Ainfsl'ieltering boxes II). Dischargeelectrode. assembly I3 is made up of the actual discharge elements I3',from which corona discharges. emanate when energized to a suitablepotential, and supporting members. It comprises attenuated members' I3.

commonly wires, depending from members l, supported in turn throughmembers le, I6 and il by insulators ld, only one of which is indicated,inboxes it on top of casing I. Orifice rings 2E permit high potentialmembers i6 to pass through the bottom oi boxes l@ without dischargingthereto. Members lbf are held taut by weights 2l. In an illustrative'apparatus which has been operated with very satisfactory results,plates 5 were spaced l2 inches apart with discharge elements i3', madeof 1/8 inch diameter {or twisted 1/8 square) rods, placed midway betweenthe plates upon '7% inch centers. Reds B' were 1/2 inch in diameter andspaced 11/2 inches apart, center to center. Rods were positioned withtheir centers 1% inches `from the surface of plate e. When plates 5 areof corrugated material the spacing from plate to plate mayadvantageously be 14 inches. Good-results have been obtained withelements i3 spaced as close together as 4 inches, center to center.

Across the bottom of electrodes '5 are aligning members` 22 andelectrode elements t' are held in alignment by horizontally extendingmembers 23 which are tied together at their ends by members 26. .Thecollecting electrodes 5 and 8 are shaken or rapped" by agitation of barwhich is connected to the several bars 22 and projects outside casing l`so. that it `may be reciprocated manually or by power means, not shown.Upon reciprocation of bar 30, electrodes 5 are pulled out of theirvertical position and strike upon members 23 and shake them, and,elements 6', being attached to members 23, are shaken also. The sides ofcasing l can be rapped from without to remove material deposited upontheir inner surfaces but it is desirable to mount stops 3l and .32 onbar 30 making this bar serve to rap the sides of the casing whilelimiting the extreme movements of bar 30. The method ori-rapping justdescribed makes rapping possible without disconnecting the currentsource. The rod curtain electrodes. E' are grounded when theyl contactelectrodes 5 but this condition offers no electrical diiiicu-lty as willbe pointed out when the method of electrode energization is described.In fact, occasionally grounding the electric charge on electrode 6appears to bea contributing factor in the dislodging of the materialfrom the' surfaces of this electrode.

Material shaken from the collecting electrodes is prevented from movinghorizontally between the electrodes by transversely positioned baillemeans 34 which tend to prevent the gas being treated from moving alongthe collecting surfaces and carrying the detached material in suspensiontowards exit 3. Baffles 34 are supported by the same structures whichsupport electrode elements 6 and are maintained at the same potential-as elements 6. Grounded plates 5 are positioned far enough away frombailles 34 to prevent sparking between these members.

Q Casing I and electrodes 5 are commonly maintained at lgroundpotential, the connection to ground being indicated at 2l. Auxiliaryelectrodes 5 are connected to a source of energy to be described laterby a conductor 25' passing through bushing 25 in one of the insulatorsS. Discharge electrodes I3 are energized through conductor 2B ininsulating bushing 26 passing through the top of one of the insulatorboxes I9.

Fig. 4. illustrates diagrammatically a preferred method of energizing aprecipitator constructed in accordance with the invention, inparticular,

the precipitator shown in Figures l, 2 and 3. AA

transformer el draws current from a single phase source ed, aballa-sting reactance 42 being utilized in the low voltage circuit forcontrolling the voltage and as a ballasting load. Arectier 43 of themechanical type revclvingin synohronism with the alternations of currentpw in source LIB recties the current fromthe highy voltage winding oftransformer il and` makes all half waves available through conductor 23at one polarity, usually negative polarity being preferred for theenergization of discharge electrodes i3. All the half waves of therectied current ilcw through conductor @5 to synchronous selector IWwhich permits every other half wave to iiow through resistance or othervoltage control B1 and conductor slit to electrode 8 and alternate halfwaves through voltage control 48 and conductorv 46 to grounded electrode5. The three groups of electrodes are insulated from one another so itwill be seen that at every other half wave, with the revolving switchesas shown, a circuit exists which includes lead 4S, electrode-5, lead28', electrode i3', and the gaseous medium between electrodes' and i3.At alternate half waves, when the switches have turned 90' mechanicaldegrees, corresponding, assuming a four pole motor revolving at i800 R..P. M., to 180 electrical degrees of a 60 cycle current source, analternate circuit is com pleted which includes conductor 25', electrodeB, lead 23', electrode I3, andthe gaseous path between electrodes 6' andI3. 4At half cycles when conductor 25' is not connected to the currentsource (as shown in the ligure) ,electrode 6 iloats, electrically, witha potential whichreachesavalue depending upon the residual potential itretains from the previous half cycle and the number of charged particlesand ions resulting from the discharge from electrode I3 which deliverelectric charges to it.

The apparatus shown in Figs. 1, 2 and- 3 'and energized with thecircuits outlined in Fig. 4 is l of particular value inremoving supendedsolid particles fromv gases. chamber I are, to a considerable degree,ionized by the strong electric fields existing alternately` Gasespassing through between electrodes I3 and 5 and between elecl Thegaseous ions become atfv tors, in particular, the conductivity of theparconducting particles when suspended in a dry gas,

v which enables them to retain their non-conductlgood conductors butwhich do not agglomerato are dicult to collect because they jump backand forth between electrodes like the pith ball in the common laboratoryexperiment, lt is to the overcoming of such diiliculties that thepresent invention is especially directed.

In the invention a quiescent zone is established, bothlas regards gasflow and electrical conditions, between collecting electrodes 5 and twhich' facilitate the collection, agglomeration, and precipitation ofsuspended particles. During the half cycle when the electric fieldexists between electrodes il? and t many of the ionized particles areriven between rods 6 and precipitated upon the surfaces of electrodes 5.During much of this period ions are continually forced toward thecollecting surfaces and upon the deposited particles and hold theparticles to the surfaces. Some oi the ions and ionized suspendedparticles are deposited at least momentarily, upon rods ii' becausethese rods are at lower potential than discharge elements i3. During thesucceeding half cycle, with the electric elds'extending from electrodei3 terminating upon electrode S, a considerable portion of the suspendedparticles may vbe deposited on the rods. Some of the particles'however,due to their momentum, to the extension of parts of the field toelectrode 5, and to local gas movements, pass between the rods. Duringthis half cycle, when the elec trodes d are not being bombarded with asurplus of ions originating adjacent the discharge fili electrodes lothe collected material on the surfaces of electrodes has an opportunityto give up to electrode 5 the charges which cause it to be attracted tothe electrode and falls immediately by gravity into a hopper providedfor the purpose below the electrodes; or, it may flutter back and forthbetween the plate and rod electrodes as it moves downwards towards thehopper. With forces alternately applied.v as described, the spacesbetween the rods remain open and a minimum of material .stays upon therods.

A complete theoretical explanation of what happens in apparatus such asthat just described is not available and will not be attempted, but theresults obtained are unique and make for increasedI efficiency in gascleaningr with electrical fields. `The shifting of one terminal of theelectric 'lield between an intermediate perforate electrode system, asillustrated by the rod curtain construction 6, and another :system hereillustrated by plates 5, makes for localized movements of the collectedmaterial as it moves downwards. The contrast between the operation of anelectric precipitator without the auxiliary periorate electrodes andapparatus comprising auxiliary electrodes in accordance with the presentinvention is striking. In the usual precipitator. when depositedmaterial of refractory electrical characteristics loses its charge. anddrops away from a collecting electrode or is repelled because it retainsor takes up charges oi` opposite sign, it wanders back into the gasstream to be recharged and reprecipitated, if effective corona dischargeis present, and asthis is repeated many of the agglom-erates and largerparticles move along the electrode surfaces towards the exit. Therequirement that this dislodged material be reionized before it isredeposited often overburdens the capacity of the apparatus, and, asmoves out into regions oi high gas velocity, it may ce carried along tothe exit before being reprecipitated. or it may move about and build uppeculiar formations on the electrode surface which are conducive to backcorona.

With the apparatus described herein, materialy breaking away from thecollecting surfaces keeps within the space between the auxiliarycollecting electrodes ii and the electrodes ii and either.reprecipitates or drops into the hopper with or without periods ofreprecipitation. The fact that the gas velocity is low in the spacesbetween the electrodes, especially when baffles are positioned acrossthe spaces as indicated by members makes for a more denite settling oithe material. Another condition favorable for precipitation is theelectric eldoi changing characteristics that extends across this space.Rod curtain or screen type electrodes have previously been placed infront of impervious collectingelectrodes either at the same potential(e. g. ground) or at such poinsulating means and independent oienergizing agencies. The results have not been as expected.

.tential as 'they can assume when suspended by Sil) With the electrodesat a common potential a araday cage condition exists making itimpossible to drive more than minor portions of the charged particlesbetween the rods unless they are spaced far apart. Instead.' thematerial collects upon and bridges across the rods. And with insulatedrods the potential is never brought to .a` denite value with regard tothe discharge electrodes,

but builds up to values approaching those on' the discharge electrodesresulting in arcing be-z tween the rods and the usually grounded plateelectrodes.

As mentioned beto-re, While the electrical conditions provided by theinvention are favorable for the dislodgernent and settling of materialwhich has been deposited and agglomerated on 'the collecting electrodesit has been found advisable to provide mechanically or manually operatedrapping means. is the mechanical forces are applied to' the platemembers between the. rods, there is no evident disturbance oi' theelectrical conditions during rapping periods. With plates 1" hanging intheir usual vertical position, electrodes t probably retain sucient Ycharge so that they never reach ground potential. But, when plates 5 androd electrodes are rapped together to dislodge deposited material.electrodes t are frequently grounded. As the half waves that energizethe system through conductor dit are permitted to build up tohigher'potential above ground than are alternate half waves conductedthroughy conductor 25', because the distance between electrodes i3 andi5 is greater than between electrodes i3 and in', it is advantageous ifnot ,necessary to lower the voltage in this circuit at tirncs ofrapping. When rapping is taking place electrode t is brought to groundpotential and. as the distance between electrodes i3 and is not greatenough to sustain the voltage set up in the circuit including conductortt,

`this voltage is reduced during rapping to approximately the voltage inthe .parallel circuit including conductor 25' by increasing resistance68 or by other means known `to the art.

bottom to form which are commonly supported by the grounded structuralframe (not shown) to which casing 6| is attached. Other rods 63 yextendparallel to each other and to rods 62. Rods 63 depend from horizontallyextending supports 13 and these aresupported by insulating means (notshown) which permits them to be energized at suitable potentials. A rowof discharge elements 64, for instance, small rods or wires, is

suspended vertically between the parallel rows l 'of rods 62 and a rowof similar discharge electrode elements 64a `is suspended between theparallel rows of rods 63. Discharge elements 64, 64a are supported byhorizontal supports 15 which are in turn supported by insulators in themanner known to the art although not indicated in the figures. It willbe noted that in this embodiment of the invention, adjacent pairs ofrods 62 and adjacent pairs of rods 63 are brought together,respectively, at top and closed links and that these links hanging inspaced relationship alongA members 12 and 13 respectively, form passageswith perforate walls for the gas being treated. It is also to be notedthat discharge elements 64, 64a

positioned in the passages or treating cells, ex-

tend above members 15 as indicated by extensions 64 vand below steadyingmembers 16 as indicated by extensions 64 so that the electric fields andresulting corona discharge will extend, 'into these end regions of thecells.

' Rods 62 and 63 may be shaken to loosen de posited material which maycling tenaciously to them by the mechanism indicated, comprising motion.

possibility of sparkover from one a horizontally extending anvilextension 69, at-

tachecl to the several pairs of rods or links making up a collectingelectrode assembly and a rapping rod 61 upon which are hammer members 68that loosely guide anvil 69 and strike against it when rod 61' is givena reciprocating A single bar' 61 can, by the proper location of sets ofhammer members 68, strike all the anvils connected to electrode links ofcommon potential. Another bar 61', spaced sufliciently distant from bar61 to eliminate the bar to the other, can be made to jar the anvils onthe alternate rows of links. While bars 61 and 61 are shown in Fig. 6 atdifferent levels for the sake of clearness, they would ordinarily'beprovided at the same levels.

The electrodes in the arrangement shown in Figs. 5 and 6 are energizedfrom a single phase source, the current being rectified and .distribnuted by mechanical switches 80,'8I in the manner illustrated in Fig. 4.Discharge electrodes 64, 64a are maintained at a high potential abovevground and at constant polarity by means of conductor 04 which isalternately connectedl to first one high voltage terminal and then theother'high voltageterminal of transformer 13. Rods 62, preferablyconnected to ground, are connected every other half cycle by conductors82 and 18 to the end of transformer 10 tlien opposite to the terminalconnected to conductor 64. A t alternate half cycles rods 63 areconnected byconductors 03 and 11 to transformer 19. The voltages'impressed between the electrodes and the electric fields set up can'beeasily comprehended by noting dotted lines 58 and 59.

When the transformer voltage is impressed acrossthe gas betweenelectrodes 64, 64a and electrodes 62 (the solid line connections at therectiilers indicate this condition) the electric fields extend from thedischarge electrode 64 to collecting electrode rods 62 as indicatedbylines 59h and from electrodes 64a to rods 62 as indicated by lines69a. lftods 63 are electrically "floating .during this-half cycle andassume a' potential intermediate thepotential o discharge electrodes 64aand ground potential. The electric fields pass through and between rods63 and terminate upon rods 62 during this half cycle and the gas andsolid particles in the precipitating space between rods 62 and 63 aresubjected to the forces of such fields during this period. Duringalternate half cycles of the energizing current when the transformervoltage is impressed across the gasI between electrodes 64, 64a and 63,electric fields are established between electrodes 64a and 63 asindicated by lines 58h and possibly between electrodes 64 and rods 63 asindicated by lines 58a. This latter relationship cannot be given withcertainty because it depends upon'the capaci tance of the transformerwindings and other conductors to ground, insulator leakage, and otherfactors but it can be stated that during these half cycles diiferentconditions of field and ion bombardment in the precipitating spacebetween electrodes 62 andL 63 do exist from the than is obtained withelectric precipitators as commonly constructed and energized.

Fig. 7 diagrammatically illustrates an arrangement of electricalapparatus which will simultaneously but independentlyenergize twoseparate groups of electrodes such as those shown in Figs. 1, 2 and 3.Transformers 89 and 00 both receive current at comparatively lowvoltages from single phase source 88 and step the voltage up to valuesrequired by the gas treater. The current supplied through transformersB9 is rectied by rotary switch S3 and caused to flow through conductorf|03 and 99 across the gas between ,discharge electrode |00 and groundedplate electrode |02.v Rectifier 04 is used to rectify the current fromtransformer 90 and this current flows through conductor |04, commonconductor 99, and the gas between electrode |00 and auxiliary collectingelectrode |0|, e. g. of rod curtain construction. Wlth the connectionsshown, full wave current at constantpolarity flows through.

both systems of electrodes simultaneously. That the voltages may be ofsuitable values and the current may beproperly divided, resistances orotherv voltage control and current ballasting means are utilized. Lowvoltage resistance 0|v and high voltage resistance 96 and 01 are incircuit comprising transformer 89 1 lll point. In other words, forexample, electrode |25,

source by conductor |04 but some current carrled by the ionized gas andcharged particles passes through electrode IBI, reaches electrode M2,and returns through conductor it. The voltage distribution is arrivedat' by trial. For instance, a voltage drop from electrode lili toelectrode m2 should provide a strong enough rleld to cause precipitationof charged particles on electrode |62 but should not be strong enough tocause disruptive breakdown of the gases be tween these electrodes.

Fig. 8 shows a schematic hooi: up using a two phase circuit |05 forenergization. With this arrangement increments of both half waves areused to energize both circuits but because of the phase relationship ofthe two phases the increments or peaks of the voltage waves areimpressed alternately between discharge electrode llt and electrode llland between electrode Ilii and electrode l 2. This is accomplished byusing very short stationary shoes H5, llt on rectiers Hi8 and ltd,respectively. If shoe llt is very short it permits only the peaks of thecurrentwaves from phase |0511 to flow through the circuit of which it isa part, including transformer tilt, and this current flow is terminatedor nearly terminated before shoe lili 'makes contact with the revolvingconnectors of rectifier lll@ and permits current to flow from phase W51)through transformer lill. By using short shoes and setting rectifier |09radially 45 mechanical degrees from rectier |03 so that advantage istaken oi the 90 electrical degree displacement of the phases, a sequenceof energizatlon is set up which comprises an electrical impulse fromphase Ita to energize the circuit which includes the gap betweenelectrode |||l and electrode |52 immediately followed by an impulse fromphase web to energize the circuit including the gap between electrodesilll and Iii. This sequence is repeated, all voltage peaks from onephase losing rectified and impressed at constant polarity across one setof electrodes and all voltage peaks from the other phase being impressedat constant polarity across the other set of electrodes but 90electrical degrees later. This system, with a single high tensionconnection H3 to electrodes llt, causes a very long peak voltagecondition to exist adjacent discharge electrode lit although groundedcollecting electrode surface M2 is used as a terminal for such conditiononly hall the time or the usual time for single phase peak waveenergization. The conditions emsting between electrode and electrodeill. Vare iavorable for precipitation and deposition of the material inthe hoppers below the electrodes.

Fig. 9 illustrates, schematically, how one single phase transformer witha mid-point terminal |2I can housed with two rectiflers |22, |23 todistribute energizing impulses in accordance with the invention. Thisarrangement leaves discharge electrode |24 continuously connected to themid-point |2| of the high tension winding of transformer |20 andalternately connects one half the winding across the gap betweendischarge electrode |24 and auxiliary collecting electrode |25 and theother half of the winding across the gap between discharge electrode |24and grounded electrode |26. By utilizing one half the transformerwinding duringone halt (say, the negative half) of the current `wave andthe other half of the transformer winding during theother half of thecurrent wave, the ends of the winding will always, when connected, be atthe saine polarity with relation to. the midand electrode |25, canalways be maintained positive with regard to electrode |24.

In all the iigures mechanical switching devices have been shown asrectifying means. Other devices such as hot cathode tubes can be used asrectiflers in some instances, examples of such use`being shown in myPatents Nos. 2,000,654 and 2,069,692.

Fig. lll shows apparatus particularly suited to the treatment ofliquids. It 'comprises a circular shell |39 open at the top (althoughthe top can be closed for outdoor use or in treatments ini volvingexplosive components) and closed at the bottom. The liquid to loetreated, for example, petroleum oil contaminated with a small amount ofwater in dispersed form, enters through inlet itl and leaves throughoutlet i32. The outlet encircles the shell near the top as an annularpassage |32 and slots |33 in the wall of the shell permit the oil topass into the culet. The liquid during 'treatment is prevented frommoving along the side of shell i3|l at any appreciable velocity bybaille means |43.

Discharge or concentrated iield electrode itil is suspended axially inthe shell from supporting structure |35 which is supported on insulators|35. Auxiliary or intermediate electrode i3? is positionedconcentrically within the shell and comprises 'torus rings,`preferablyoi metal tubing, vertically spaced and supported by metal struts |39.The composite electrode or cage i3? is supported on a horizontal openframe it@ and this frame is supported in desired position by insulatorsMl in remote boxes |43. Electrode i3d is energized through conductor|26' and electrode |37 is energized through conductor |25' passingthrough an insulator ldl. Conductors |25 and l 25' are connected to asource of energy suc'h as that shown in Fig. Al and shell i3d isgrounded.

The electrical and hydraulic conditions present in the apparatus, in theregion between electrode G3i' and shell |39 in particular, are Favorablefor the. agglomeration and collection oi the water particles. The Watercollects in masses large enough to overcome surface tension and otherbuoyant forces and settles to the bottom o the apparatus to be drawn oiTthrough pipe l Il.

The term non-discharge electrode, as used herein, is intended to denotean electrode of such configuration as to substantially prevent orminimize corona discharge therefrom at elevated potentials below the,potential at which disruptive discharge occurs.

I claim:

1. Apparatus for electrically treating a fluid comprising a dischargeelectrode, two non-,discharge electrodes insulated from the dischargeelectrode and from each other and means for alternately establishing anelectric eld between the discharge electrode and each of said non'-discharge electrodes.

, 2. Apparatus for electrically treating a fluid comprising a dischargeelectrode, two non-dis-v charge electrodes insulated from the dischargeelectrode and from each other and means for establishing an electricleld between the discharge electrode and each of said non-dischargeelectrodes, including means for independently varying the strength ofthe electric fleld'hetween the discharge electrode and at least one ofsaid non-discharge electrodes.y

3. Apparatus roi' electrically treating a iluid comprising a dischargeelectrode, two non-discharge electrodes insulated from the dischargeelectrode and from each other, and energydirecting means forestablishing independent unidirectional electric fields of the samepolarity between said discharge electrode and each of said non-dischargeelectrodes.

4. Apparatus for electrically treating a fluid comprising a`dischargeelectrode, two non-discharge electrodes insulated from the' dischargeelectrode and from each other, energy-directing means for establishingunidirectional electric fields of the same polarity between saiddischarge electrode and each of said non-discharge electrodes and meansfor independently Varying the strength of at least one of said fields.

5. Apparatus for electrically treating a fluid stream comprising adischarge electrode, a collecting electrode spaced from the dischargeelectrode, a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode, and energy-directing means forestab-- lishing independent intermittent electric fields of the samepolarity between the discharge electrode and the other two electrodes.

6. Apparatus for electrically treating ya vfluid stream comprising adischarge electrode, a coll lecting electrode spaced from the dischargeelectrode, a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode, and energy-directingmeansestablishing independent discharges between the discharge electrode andthe other two electrodes.

7. Apparatus for electrically treating a fluid stream comprising adischarge electrode, a collecting electrode spaced from the dischargeelectrode, a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode, and energy-directingmeansestabiishing dual electric fields from the discharge electrode, oneof the said elds terminating on the collecting electrode and the otheron the nondischarge electrode.

8. Apparatus for electrically treating a fluid comprising a dischargeelectrode, a collecting electrode insulated from the dischargeelectrode, a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode and insulated from both the otherelectrodes, and energy-directing means whereby an electrical field isestablished between the discharge electrode and the non-dischargeelectrode.

9. Apparatus for electrically treating a iiuid comprising a dischargeelectrode,l a collecting electrode insulated from the dischargeelectrode. a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode and insulated from both the otherelectrodes, and energy-directing means whereby an electrical field isintermittently established between the discharge electrode and thenon-discharge electrode.

10. Apparatus for electrically treating a uld comprising a dischargeelectrode, a collecting electrode insulated from the dischargeelectrode, a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode and insulated from both the otherelectrodes, and energy-directing means whereby an electrical Held isestablished between. the discharge electrode and the collectingelectrode.

11. Apparatus for electrically treating a fluid comprising a dischargeelectrode, a collectingelectrode insulated from the discharge electrode,

a non-discharge electrode positioned between the -discharge electrodeand the collecting electrode and insulated from both the otherelectrodes, and

energy-directing means whereby an electrical.

iield is. intermittently established between the discharge electrode andthe collecting electrode.

12. Apparatus -for electrically treating a uid stream comprising adischarge electrode, a col.- lecting electrode spaced from the dischargeelectrode, anon-discharge electrode positioned between the dischargeelectrode and the collecting;

electrode, means for establishing independent intermittent electricfields of the same polarity between the discharge electrode and theother two electrodes and bafiie means positioned `to at least partiallyshield the space between the non-discharge and the collecting electrodesfrom the flow of the fluid stream.

13. Apparatus for electrically treating a uid stream comprising adischarge electrode, a collecting electrode spaced from the'dischargeelectrode, a non-discharge electrode positioned between the dischargeelectrode and the collecting electrode and closer to the collectingelectrode than to the discharge electrode. and means for establishingindependent intermittent electric iields of the samepolarity between thedischarge electrode and the other two electrodes. 4

14. Apparatus ior electrically treating a fluid stream comprising adischarge electrode structure extending in the direction oi' iiow of thestream, a collecting electrode structure spaced from and parallel tosaid ldischarge electrode structure' an additional non-dischargeelectrode structure positioned between said discharge electrodestructure" and said collecting electrode structure, baille meanspositioned in the space between .the collecting electrode structure andthe non-discharge electrode structure, and means for establishingindependent intermittent electric elds of the same polarity between thedischarge electrode structure and the other two electrode structures. I

l5. Apparatus for electrically energizing a treater having a dischargeelectrode system and two non-discharge electrode systems comprising ahigh voltage transformer having its low voltage winding connected to asource of alternating current, means connecting the mid-point of thesecondary winding of the transformer to the discharge electrode systemand means connecting each of the terminals of the secondary with one ofsaid non-discharge electrode systems including energy-directing devicesadapted electrically to connect eachv of said non-discharge systems withthe corresponding terminal only at alternate and opposite half-cycles ofalternation.

16. Apparatus for electrically energizing a tr later having a dischargeelectrode system and two non-discharge electrode systems comprising apair of high voltage transformers having their low voltage windingsconnected to the same source of .alternating current, means connectingsaid electrode systems with the secondary Windings o f said transformersincluding energy-directing devices adapted to connect said dischargeelectrode system to each of said secondary windings at terminalsof thesame=polarity in synchronism with the alternations in current and toconnect each of said non-discharge electrode systems in alternation tothe opposite ends oi.' one of said secondary windings. g

17. A method of treating fluids which comprises passing a fluid in astream adjacent a zone of relative quiescence. establishing a highpotential ileld across said stream and causing said eld to terminate inalternation on electrode surfaces on each side of said zone of relativequiescence.

18. A method of treating iiuids which comprises passing a fluid in astream adjacent a zone of relative quiescence, establishing a highpotential iield across said stream, causing said eld to terminate inalternation on electrode surfaces on each side of said zone of relativequiescence and varying the potential of said eld with each alternation.

19. A method of treating iiuids which comprises passing a stream offluid along a discharge electrode system and adjacent a quiet zonedeiined by two non-discharge electrode systems and subjecting said fluidalternately to a high p0- tential electric i'ield terminating on one ofsaid non-discharge electrodes to charge particles in the iiuid streamand initiate movement of the discharge electrodes, a. plurality of setsofl permeable non-discharge electrodes spaced from said dischargeelectrode sets, circuit elements electrically connecting said sets ofnon-discharge electrodes in two groups, each consisting of alternatingsets of non-discharge electrodes, with said discharge electrode setswhereby independent intermittent electric fields of the same polaritymay be established between the sets of discharge electrodes and each ofsaid groups of non-discharge electrode sets.

22. Apparatus for electrically treating a iluid stream comprising aplurality of sets of discharge electrodes extending transversely of saidgas stream, a plurality of sets of permeable nondischarge electrodesspaced from said discharge electrode sets, circuit elements electricallyconnecting said sets of non-discharge electrodes in two groups, eachconsisting of alternating sets of non-discharge electrodes, with saiddischarge 'electrode sets whereby independent intermittent electriciields of the same polarity may be established between the sets ofdischarge electrodes and each of said groups of non-discharge electrodesets.

23. A method of removing suspended material from a fluid which comprisespassing a stream of the fluid adjacent a quiescent zone, establishing anelectric eld across said stream and intermittently extending said iieldacross said quiescent zone whereby suspended particles in the iiuid aretransported into the quiescent zone and are therein lpermitted to settleby gravity into a removal zone displaced from the iiuid stream. A

24. A method of treating fluids which comprises passing a stream offluid along a discharge electrode system and adjacent a quiet zone denedby two non-discharge electrode systems and subjecting said fluid to ahigh potential electrical neld terminating on one of said non-dischargeelectrode systems while maintaining `the other non-discharge electrodesystem substantially insulated from the rst non-discharge electrodesystem and from the discharge electrode system. I

HARRY A. WINTERMU'I'E.

